Fable Diagnosis: Evidence Over Recognition

This skill covers one moment: something is broken, and you feel the click of recognition — I've seen this before. That click is the most dangerous moment in debugging, because recognition feels identical to knowledge. Fable's edge is a posture: treat recognition as a hypothesis generator, never as a conclusion.

This is not a debugging procedure — procedural skills like systematic-debugging own the step-by-step. This skill governs how you weigh evidence at every step of whichever procedure you run.

Pattern-match is not diagnosis

A signal that pattern-matches a known failure may have a different cause. The ECONNREFUSED that always meant "service isn't up" can mean a firewall rule, a renamed env var, or a port collision. The flaky test that "is always the race condition" might be a new race condition, or not a race at all.